**6. Discussions**

In these trials of molding dies and glass product manufacturing, we were able to obtain research results for a specific aerospace field. The surface roughness of polished molding dies accuracy is below 0.02 μm in *Ra*, if the required accuracy is more than it, this polishing techniques for stainless steels will be used in other manufacturing fields. On the other hand, the surface roughness accuracy of formed glass plates is kept with original glass plate one. This result means that the surface roughness accuracy of the formed glass plate does not depend on the surface accuracy of the base molding die, so it is expected to be a useful result in the conventional manufacturing of optical products.

In recent, molding dies with high precision surface roughness and very small shape error are required in real glass product, such as super mirrors used in X-ray telescopes. If we consider that these techniques will become a molding dies and glass products manufacturing method, the manufacturing cost and manufacturing period of optical products will be shortened, and continuous manufacturing efficiency can be expected in the future. However, optical components used in aerospace field are one of kinds of items and are not produced in large quantities and continuously. When this technology is applied as a manufacturing technology for other products, it will be useful in the industrial field not only as a specific manufacturing technology but also as a sustainable manufacturing technology.
